#include <stdio.h>
int main(void)
{
    printf("请输入一个整数");
    int n;
    
    scanf("%d",&n);

    char arr[10];
    int i=0;
    while(n!=0)
    {
        int temp=0;
        temp=n%16;
        switch(temp)
        {
            case 1:
                arr[i]='1';
                break;
            case 2:
                arr[i]='2';
                break;
            case 3:
                arr[i]='3';
                break;
            case 4:
                arr[i]='4';
                break;
            case 5:
                arr[i]='5';
                break;
            case 6:
                arr[i]='6';
                break;
            case 7:
                arr[i]='7';
                break;
            case 8:
                arr[i]='8';
                break;
            case 9:
                arr[i]='9';
                break;
            case 10:
                arr[i]='A';
                break;
            case 11:
                arr[i]='B';
                break;
            case 12:
                arr[i]='C';
                break;
            case 13:
                arr[i]='D';
                break;
            case 14:
                arr[i]='E';
                break;
            case 15:
                arr[i]='F';  
                break;
            case 0;
                arr[i]='0';
                break;
        } 
        i++;
        n/=16;                
    }

    putchar(arr[2]);
    putchar(arr[1]);
    putchar(arr[0]);
    return 0;
}